Apparatus for molding



Dec. 8, 1953 E. BLAUROCK APPARATUS FOR MOLDING Filed June 1, 1950 Ill! 32 5 ATTORNEY Patented Dec. 8, 1953 APPARATUS FOR MOLDING Edward E. Blaurock, Fort Wayne, Ind., assignor to United States Rubber Company, New York,

N. Y., a corporation of New Jersey Application June 1, 1950, Serial No. 165,463

2 Claims.

a malleable metal support therefor, the support was held in place in the mold by clamping between the mold halves the portion of the metal from which the plastic was to be excluded. The plastic was bonded to the portion of the support exposed to the plastic in the mold cavity. Due to the fiowable characteristicof the plastic and the pressure applied thereto in the mold, it flowed out between the mold halves and over certain areas of the metal support clamped therebetween',

and became bonded to the areas where it was not wanted. After the composite article was removed from the mold it was necessary to remove the unwanted plastic from the surfaces'of the metal,

' which materially increased the cost of the article due to the use of extra equipment and the expenditure of labor and time.

In accordance with the present invention the composite article is made by molding the desired plastic onto the pro-formed insert or support as heretofore, but the flash or overflow from the mold cavity is excluded from the desired areas of the preformed part by clamping the malleable part between the mold parts and impressing hard barriers extending from the mold parts into the malleable surface of the preformed part. Such barriers may eitherv confine the plastic to the mold cavities or shield the desired areas of the preformedpart from the flash or overflow from the mold cavity. The barriers may be in the v form of a hardened ridge which surroundsthe mold cavity so as to prevent the flow of any flash therefrom, or the barriers may be located away from the rim of the mold cavity and surround the I area from which the plastic is to be excluded.

This invention will be further described in reference to the accompanying drawings, in which:

Fig. 1 is a cross-sectional view of a composite plastic and metal article, which was made in accordance with the practice of this invention;

Fig. 2 is a top plan View of the improved cavity containing mold part embodying this invention; Fig. 3 is an exploded cross-sectional view of the mold parts, including the cavity containing part taken on line 3--3 of Fig. 2, in which the 2 cavity is filled with plastic to be molded onto the metal part interposed between the mold cover and the cavity containing part of the mold;

Fig. 4 is a cross-sectional view of a modified form of mold embodying this invention, in which the plastic and metal part which forms the composite article is enclosed between the mold cover and the cavity containing part of the mold;

Fig. 5 is a plan view of a portion of the metal support and the cavity containing part of the mold looking in the direction of the arrows on line 55 of Fig. 4; and

Fig. 6 is a cross-sectional view of a, portion of another form of the moldin its closed position and showing a portion of a composite article similar to the one in Fig. 5 being molded therein.

In the practice of this invention, the composite article II] containing the plastic II and malleable metal support I2, shown inFig. 1, may be made by the use of the novel mold I3 embodying this invention, as shown in Figs? and 3. As shown in Fig. l, the plastic of the composite article I0 comprises a vulcanized soft rubber cushion II which is bonded tothe malleable metal support I2, which is rectangular in form, and may be attached to an object to be supported on the rubber cushion I I by means of bolts, or screws, or other fastening elements, which are not shown but-are adapted to pass through the apertures I4 in 'the plate I2 and into the object.

The rubber II is molded onto the desired portions of the plate I2, and is excluded from the other portions of the plate by the mold I3 shown in Figs. 2 and 3, which comprises a cavity containing part I5 and a top -cover IS. The mold cavity part I5 is provided with a cavity I! having a hardended insertIB which surroundsthe top rim of the mold cavity, and is provided with a V-shaped ridge I9, which projects I slightly above the plane of the top face 20 of the cavity containing part I5. Pins 2I are anchored in mold part I 5 in position to project into the holes I4 in the metal plate I2, and corresponding holes 22 in the top cover I6, so as to orient such parts in respect to the mold cavity IT. The vulcanizable raw rubber plastic composition 23 is placed in the mold cavity IT. The metal plate I2 and the mold cover I6 are positioned over the pins 2 I, and the assembled parts are placed in a vulcanizing press (not shown), which'exerts pressure on the top of the cover I6 andthe bottom of the mold cavity containing part I 5 so as to force the parts together. The vulcanizing press supplies suflicient pressure to force the hard ridge I9 into the malleable surface of the metal l8 may be made of hardened steeltandtpressed into the groove 25 around the rim of the cavity l1.

The metal plate I2 is treated in-the well known manner to condition its surface so that'the raw vulcanizable rubber plasticr23 will be bonded-stothe surface during its vulcanization in the vulcanizing press. Upon the removal Of' thescomposite article Ill from the mold l3 the surface ofitheplatee- I2 will-=be f-reexfromrsany adhering .=rubber-,other than-the cushiona l lgwhich-iscontained within the groove- 24-.formed--.byzthe-rbar- Jrierl ridge vI 9. :T'JIII someicases, it may .beimpractical to con- Lil-fine the plasticto thermold cavitybyzmeans of a surroundingridge 19: asshown inFig. 3,- because: of. the great size" of- 1 the cavity. that may :-be required, or-because of vthespeculiar shape of ..--t-the preformed: insert or'su'pport onto which the plastic isto be molded In such event,:the plastic flows between the mold-ipartspland it may be desirable to-exclude the plastic flash or overr'sflow from r'certainselected-=portions ofthe" insert or-.csupport'- that may". hex-clamped. between the moldtpartst Aneexample. of :thewmanufacture oi LirSllCha a :composite. article is .i-llustrated in- Figs. 4-, 5.-and 6. 1 Referringto Eigs-hirand 5,l-themold 1-46 comprises a cavity-containing part 2'! and a setup-mold plate ZBZ'iWhlCh' is -providedw-ith aperwturesr29 adapted torreceivethe pins30 in-mold cavitypartZ-I for orienting-the top cover: 28\with respect to: the mold cavity 3|, which--contains plastic -vulcan-izable raw I rubber 32-. being -molded onto and bonded to -a --ma-llea-bl metalplate supt-mort'33 in a vnlca-nizing pressrtnot shown) The crzplate 33-is-in theform of a :strip; assshown in :Fig; 5;:Whi01b extends. across :the-moldcavity 3 l laHdTdOGS': not cover the entireperimeterthereof.

The plate 33 is providedwith-ears 34=which-are qwprovided with-apertures 31 'forzanchoring the plate: inthe finished compositerarticleato an object to be cushioned. The apertures 3T are also: usedto orient the plate 33- in. respect to: the

- s-:mold cavity 3|; by placingthem around the. pins 30. It is" desirable: to.preventftheentrance of 1;; any \flashfroml the-Jmold. cavity: 3 llinto theapertures .3l-,-because it becomesbonded to. the! edges thereof and mustsbe removed to permit the fasiz-iteningr elements to. enter. the --'apentures,' I For 1 thexpurpose of excluding the flash, hardenedring ss-rinserts 38- are located in'recesses around the pins r3flzinithe cavity containing-apart 2'! of the mold -26; -:The ring -inserts- 38 are providedwitheleawaited 1 circumferential ridges 39, i which. are-:im T pressed? intc'the-malleable surface of the ears @114 under the pressure of the. vulcanizingpress, so as to form abarrieraround theapertures. 31 in "theiplate- 33, so-as to-excludethe flash fromthe :--=-apertures 31.

I w-Inrtheexample asshownin Figs; 4. and 5.the i .fiash from'the cavity 3l sometimes flows'around ..::-the strip plate 33'and flows between th .top suricfaceofvthe ears 34 andthe mo1dcover28. In if'thecase where-the cars 34.- are. relativelylthin,

this flow of flash is prevented from entering the upper side of the apertures 31 by virtue of the deflection of the upper surface of the ears 34 against the bottom surface of the mold cover 28 5 in the areas opposite the barrier ridges 39. In other words, a ring of metal on the top surface of the ears 34 opposite the ridges 39 is tightly 7 'pre'ssed ag'ainst the' 'bottom surface of the mold cover- 28 to form a -seal around the apertures 10 31 so as to exclude any flash on the top surface of the ears 34 from entering the apertures 31. r..- rAfter..--the raw vulcanizable rubber composition 32 has been vulcanized in contact with the plate 33 in1hthe .vulcanizing press as previously de- 5= scribed-in reference to Figs. 1 to 3, the rubber is bonded to the plate 33, and the composite articles: may be removed from the mold.

Instead of" relying on the deflection of the iii-malleable metal insert or support around the anchoring apertures therein for the prevention w of; therplastic -from: entering the; apertures in the ears fromthe-top-side.thereofsas shown-in-Fig. 6, 1: camaised-h-ardened insert 43 mayv .beaplaced. in-the :0 mold cover Mas well asan insert 4!] imthecavity 1' -plate.42'. Theuse of the secondlbarrierrmgAl) in ..-r the moldcover. 4.! "may .be.:necessary in. the .case =where thesplastic-43- is molded-onto a thick m'etal plate 44,-Wh0se surface...on .one side lwill not be defiectedby Jthe hardened-rim ofx the-barrier insert -on-the. oppositeside of L the .plate. As :shown in- Fig. -6 thebarrieninsert. rings..4ll :may-bemade .m -flaton :top instead air-being provided 'withcnarrowcircular ridges, as shown on the .insertrings previously described.. In. the case'. oil-fiat .vsided -.insert..-rings m-slightlyrmore area ofllthe. .metal .plate 44 issdisplacedt around. the apertures. 45 in the plate 44 than-.in the. caselwhere .theanar-row --r,idges are used;but in-either :caseLthefiashirom :theraw-ivulcanizable rubber-voompositiontfl is (prevented. from entering the. "apertures .in the ----plate,z :anchthe necessity: of. memovingthe rubber -.-flash from. the apertures .and the" areaaadjacent .thereto. oftthel plate. aftenthe molding; operation is .-eliminated. .J. While several-forms of this invention-:haverbeen .V.described herein-more or less. in detail it will be understood that changes maywbenmadeinnthe wmethod and, apparatus without-departing? from mthmspirit; of. this \irrventiorrzand the scope of the 50. appendedclaims.

:Havingmthus: described ;my :irrvention awhat I :claim .andt desireatot protectby Letters" :Patent Y is:

l-rv A emetal moldicomprising: at-tleaststwmparts :having; cooperatingtfacesrbetween'kwhich. amialcable: metal-part is adaptedvtoa'be. olamped;:one .ofz -sa-idz molctzpartszhavingzai moldzcavityztherein zrgior receiving-z-plasticianaterial; ton-be moldedm'nto :.:-:thenialleable metals part;:zlocatingtpinsr:on;one fiormoldaparitzzadaptedto=:be received ,-'-by.w .locating ecesses in. the -:other. mold -.-part and by locating recesses in the :malleablo metale part :WheIlnDOSli0ned:between said mD1d--parrtS,GOUIItGIYfI'BCGSSBS 1 issurroundingvsaid pins inrsaidmold part-a containing'said: cavity, airing-harder than saidmoldrf-ace .mlocated inieach of-1 said.counter recessesand proj'ecting beyondasaid iace- -ofz said-mold; pant; said s-projecting. portiorr oflsaidming being adapted to be-pressed. into; the malleablermetalpart-to: form a barrier-against theoflow .Ofr': plastic fromasaid ,-T --mold.cavityinto the locating-hole in the-malleable m-metal-lpart.

2.Amoldmomprising,twoapartss one of said .;parts ,having -,a mold cavitytherein,;superimposed recesses in eachi-oftsaidunoldparts --.located.-ad-

jacent to said mold cavity, locating pins adapted to be received by said recesses and by recesses in a malleable metal part adapted to be clamped between saidmold parts, said recesses in both of said mold parts having counter recesses surrounding said first mentioned recesses, a ring harder than the remainder of said mold located in each of said counter recesses and projecting beyond the parting surfaces of said mold parts, and said raised portion of said rings being adapted to be pressed into the malleable metal part to thereby exclude said moldable material from the locating recesses therein.

EDWARD E. BLAUROCK.

References Cited in the file of this patent Number UNITED STATES PATENTS 

